title: Quantitative observation of focused-ultrasound-induced vascular leakage and deformation via fluorescein angiography and optical coherence tomography.
abstract: Focused ultrasound (FUS) is a recently discovered noninvasive technique for local and temporal enhancement of vascular permeability, which facilitates drug delivery from the vessels into the surrounding tissue. However, exposure to FUS at a high intensity may cause permanent damage. To investigate the effects of the FUS treatment on blood vessels, we propose to use fluorescein angiography (FA) and optical coherence tomography (OCT) for real-time observation of the diffusion of fluorescence dye from blood vessels and to evaluate the morphological changes of the vessels in vivo. With time-resolved FA imaging, the relationship between the exposed power and the improved permeability of the vessels can be assessed according to the enhancement of the fluorescent intensity due to the dye leakage. Furthermore, the variation of the time-resolved fluorescent intensities can be used to identify the occurrence of dye leakage. In contrast, OCT can be implemented for the reconstruction of tissue microstructures. To quantitatively evaluate the morphological changes of the vessels after the FUS exposure with OCT, a new algorithm was proposed to estimate the vessel area based on the comparison of backscattering properties resulting from the tissue and vascular structures. Results showed that the vessel area increased as the exposed power increased, and the area became significantly larger at a higher FUS exposure power of 10 W. In conclusion, integrated FA and OCT observation can be potentially effective for monitoring the outcome and investigating the effects of FUS treatment.
authors.affiliation: Department of Electrical Engineering, Chang Gung University, 259 Wen-Hwa 1st Road, Kwei-Shan, Taoyuan 33302, Taiwan.
authors.forename: Meng-Tsan
authors.initials: MT
authors.lastname: Tsai
authors.forename: Cheng-Kuang
authors.initials: CK
authors.lastname: Lee
authors.forename: Kung-Min
authors.initials: KM
authors.lastname: Lin
authors.forename: Yu-Xiang
authors.initials: YX
authors.lastname: Lin
authors.forename: Tzu-Han
authors.initials: TH
authors.lastname: Lin
authors.forename: Ting-Chia
authors.initials: TC
authors.lastname: Chang
authors.forename: Jiann-Der
authors.initials: JD
authors.lastname: Lee
authors.forename: Hao-Li
authors.initials: HL
authors.lastname: Liu
mesh_terms: D000465:Algorithms; D000818:Animals; D001808:Blood Vessels / Q000000981:diagnostic imaging* / Q000528:radiation effects*; D004423:Ear / Q000098:blood supply; D005451:Fluorescein Angiography / Q000379:methods*; D007091:Image Processing, Computer-Assisted; D008297:Male; D051379:Mice; D041623:Tomography, Optical Coherence / Q000379:methods*; D014464:Ultrasonic Therapy / Q000379:methods*; D014463:Ultrasonography